Overspeed control for hoists



n; F. LEPLEY. OVERSPEED CONTROL FOR HOISTS.

APPLICATION FILED IAN. 22l I92I.

` Patented June 13, 1922.

\ 2 SHEETS-SIIEET 2.

e2 @tra e ein rs OVERSPEED CONTROL FCPR EOISTS.

Application filed January To all whom t may concern.'

Be it lrnown that l, DANrnL F. LnrLnY, a citizen 'of the United States, residing at Connellsville, in the county of Fayette andl State of Pennsylvania, have `invented a new and useful Overspeed Control for Hoists, of which the following is speci'czition.

This invention relates to an overspeed control for hoists, one of the'objects of the invention being to provide a mechanism for use in connection with the drum oi an inclined hoist such as shown, for example, in Patent No. 1,294,124-, issued to me on Feb. l1, 1919, whereby the drum will not stop suddenly but will be kept underv control up to, and maire a gradual ystop after the normal retardation periodot' the hoist has begun, the operation of this mechanism being automatic. n

lt is a lwell known fact that in all large slope or inclined hoists where long and heavy trips of cars are lowered, there is danger or' excessive speed and costly wrecks where there is the slightest inattention on the part of the hoist operator. lt is also a recognized tact that in vertical shaft hoists, where the drums are fast upon the shafts, excessive speed due to the lowering of heavy unbalanced loads often results in wrecking or seriously injuring the motor. These objectionable results have heretofore been overcome by making :in emergency application of thevbrakes in order to bring the drums and motor to a sudden stop] ln most cases this is as dangerous as the overspeed because it is likely to result in broken ropes or connections on cages or cars as well as injury to the armature windings oi the motor.

An object of the present invention is to overcome the objectionable features by automatically maintaining the drum under control so that it can be gradually stopped as heretofore explained. n

A still further object is to provide a brake mechanism by means ot which there can be yobtained a closer brake regulation with less manual eiiort than 'has heretofore been possible.

Another object is to provide a brake mechanism in which the maximum brake ymovement per unit of lever movement, is

at the point of ztulll application instead of at the point oi iull release.

With the foregoing and other objects in to produce the results desired.

Speciieation of Letters Patent. Patgmtd June 13 192.2.

, 'i3-2l. Serial No. $9,206.

viewwhich will appear as the description proceeds, the invention resides in the combination and arrangement of parts and in the vdetails of construction hereinafter described and claimed,'"it being understood that, within the scope of what is claimed, changes'in the precise embodiment of the invention shown can be made withouty departing 'from the spirit of the invention. ln 'the accompanying drawings the preierred iorm oi the invention has been shown.

ln said drawings- Figure l is an elevation of that portion' oit a hoist mechanism constituting-the present invention certain co perating parts being shown.

Figure 2 is a .iront elevation of a portion of an air brake engine forming a part `of the mechanism and showing parts of the overspeed'regulator in position thereon.

Figure 3 is a section through'the casing i of the air actuated its connection. n

Figure 4 is a section through the governor controlled valve forming a part of the mechanism. f

Figure 5 is a plan view of the cam bar and cooperating parts. f

Figure 6 is a side elevation showing a portion of the means for shifting the valves ot the air engine. f

Referring to the iigures by characters of reference l designates a weighted arm fulcrumed es at 2 and connected by a rod 3 to the lever ivwhich, as shown, is connected to the brake'members 5 engaging the drum 6 oi the hoist. The arm l is adapted to be actuated by air operated mechanism indicated generally at 7, the operation of this mechanism or engine being controlled by a governor 8 which receives its motion through Vsuitable power transmitting mechanism 9 from the drum 6 .and conplunger and showing,

ltrolsthe actuation of a slide valve l0 shown they cooperate with the present invention Mounted on the air brake engine "7 is a casing 15 provided with a bore 16 in which is slidably supported a plunger 17. The pipe 14 leads to the bottom of this bore so that when the drum is rotating at proper speed and the valvelO is `supported in normal position by the governor 8, there will be a pressure of air from the pipe 12 and through the casing 11 to the pipe 14 suiiicient to hold the plunger 17 in raised position.

The plunger 17 is connected by a link 18 to a crank arm 19 extending from a shaft 2O journaled in the casing 15. One end of the shaft 2O is provided with a radial arm 21 normally extending horizontally` and provided with an adjustable weight 22, this arm constituting means for moving the plunger 17 downwardly `when relieved of the supporting action of the air thereunder. Another arm 23 extends downwardly from said end of the shaft and has an adjustable weight thereon as shown at 24, this arm acting as a pendulum and constituting a stabilizing medium.

Extending from the other end of the shaft 2O is Va crank arm 25 having a link 26 eX- tending downwardly therefrom forked and slotted longitudinally as shown at 27 and which straddles the operating `end. of the "floating lever 28 which operates the valve gear of the engine 7. It will be noted that the valve gear is connected to the arm 1 by a rod 29 attached to one of the arms ofthe valve gear lever 29. See Figure 6.

Obviously in the eventof total failure of air in the system the pendulum arm 28 will swing to a substantially vertical position and the plunger 17 will move downwardly within its casing 1,5. The arm 1 will drop of its own weight and the brakes `will be applied as has been disclosed in mechanisms of` this type heretofore patented kby me and one of which has been illustrated in my patent hereinbefore mentioned. It might be stated that a pin 30 is carried by the lever 28 and projects into the slots 27 so that the link 26 and the lever 28 are thus constantly connected. After .air pressure is restored in the system it will exert a lifting action upon the plunger 17 with the result that the pen dulum arm 23 will `be swung laterally and upwardly against a limiting stop 31 provided therefor and atthe same time the weighted arm 21 and the link 26 will be elevated. Thus when the operating end of the counterweighted floating lever 28 of the engine valve mechanism is raised to the position 1t assumes when the brake 1s fully released, the pin 30 will assume a position Awithin the top end of the slot 27. `Obviously the pendulum arm will respond to the slightest reduction of air pressure under the plunger 17 `and will swing downward toward a vertical position as the pressure is reduced but will stop and remain stationary in any position at which the corresponding air pressurewill balance it and will immediately assume its normal position upon the restoration of the normal air pressure. The movement thus imparted to the lever 28 and the `corresponding actuation of the valves of the air engine 7 will result in a brake application or release as the case may require. Any degree of reduction in the air pressure under the plunger 17 will make a correspondingpower brake application by forcing the operating end of the lioating lever 28 downward (even against the power of the hoist operator) thereby to apply the brakes. As soonas the air pressure increases under the actuating yplunger it will effect a corresponding'release of the floata shaft constituting the fulcruin thereof and extending from this shaft and movable ywiththe lever 32 are` parallel arms 42 having a roller 48 journaled between the free ends thereof and working within a V-shaped cam slot 44 formed within a cam bar 45 which is slidable between the arms 42. This bar has a longitudinal slot 46 through which the shaft 33 extends and one end of the bar is guided within a bracket 47 as shown. The other end of the bar is pivotally connected to one arm of a bell crank 48 the other arm of which is attached to the operating end of the floating lever 28 by a link 49.

l? rom the foregoing it will be noted that when the brake operating lever 32 is in its central or intermediate position the roller 48 will be located in the center of the cam slot 44, the bar 45 being shifted to its left the brake mechanism and permit it to be actuated by the automatic air controlled means heretofore described.

lVha-t is claimed is 1. In hoist mechanism the combination with a brake, a pressure operated engine, means operated by theengine for applying and releasing the brake, and a floating lever `for controlling the actuation vof the engine,

ofa weight controlled plunger` means for directing pressure against the plunger to offset the actionof its controlling weight, a governor controlled valve for regulating the miente llow ot pressure to the plunger, a hand operated lever for shifting the floating lever to actuate the engine and release the brake, and means operating automatically by the failure ot pressure against the plunger for automatically shifting the floating lever to apply the brake.

2. In hoist mechanism the combination with a brake, a pressure operated engine, means operated by the engine for applying and releasing the brake, and a Heating lever for controlling the actuation of the engine, or a Weighted lever, a plunger movable therewith, means for directing pressure against the plunger normally to overcome the action of the weighted lever, a governor controlled valve for regulating the pressure against the plunger, a hand operated brake controlling lever, means operated by the movement of the lever in either direction from its central position for shifting the floating lever to actuate the valves of the engine to release the brake, and means operated by the actuation of the plunger when relieved et its pressure for shifting the Hoating lever to brake applying position.

3. The combination with brake mechanism of a hoist and a pressure operated engine for actuating said mechanism, oi a Hoating lever for controlling the operation of the engine, a hand lever, and means operated by the movement of the hand lever in either direction from its central position for shifting the floating lever to release the brake, a plunger, meansy for directing pressure against the plunger to hold it normally in one position, a weight for actuating the plunger when relieved of pressure, a governor controlled valve for regulating pressure against the plunger, a link movable with the plunger, and a limited slidable connection between said link and the Hoating lever.

4. In a hoist the combination with a drum, a brake therefor and an engine for controlling the application of the bralre, of a Hoating lever for controlling the actuation of the engine, a hand lever, means operated by the movement of the lever in either direction from its central position for shifting the Heating lever to release the brake, a plunger, means for directing pressure against the plunger normally to hold it in one position,

a governor controlled valve driven by the drum for regulating pressure against the plunger, gravity operated means for actuating the plunger when relieved of pressure thereagainst, and a member movable with the plunger and having a limited slidable connection with the Heating lever.

5. ln hoist mechanism the combination with a drum, a brake, an engine for actuating the same and a Hoating lever for controlling the actuation of the engine, of a' hand lever,

arms extending from the fulcrum of the hand lever and movable therewith, a bar slidable between the arms and having a cam slot, means carried by the arms and working within the cam slot for shifting the bar longitudinally in one direction during thel movement of thehand lever in either direction from its central position, and means actuated by the bar for shifting the floating lever to control the actuation of the engine.

6. In a hoist the combination with a drum, a brake, an engine for actuating the brake and a Heating lever for controlling the actuation of the engine, of a hand lever, an arm movable therewith, a bar slidable relative to the arm, said bar having an angular cam slot, means carried by the arm and movable within the slot for shifting the bar longitudinally in one direction when the lever is moved in either direction from its central position, and means for transmitting motion from the bar to the actuating end of the Hoating lever.

7. The combination with brake mechanism of a hoist and a pressure operated engine for actuating said mechanism, of a Heating lever for controlling the operation of the engine, a hand lever, and means operated by the movement of the hand lever for shiftingk the Heating lever to release the brake, a plunger, means for directing pressure against the plunger to hold it normally in one position, a weight for actuating the plunger when relieved of pressure, a governor controlled valve for regulating pressure against the plunger, and a relatively movable connecting means between the hand lever and the plunger for allowing actuation of the floating lever by the hand lever independently of the plunger.

8. The combination with brake mechanism of a hoist and an engine for actuating said mechanism, of means for controlling the operation o the engine, a lever, means operated by the movement of the lever for shifting the controlling means to release the brake, weighted means, means ordirecting pressure against the weighted means to hold it normally in one position, a governor controlled valve for regulating the pressure against said weighted means, and a connection between the lever and the weighted means for allowing actuation of the controlling means by the lever independently ot the weighted means.

In testimony that I claim the foregoing as my own, I have hereto aHXed my signature in the presence of two witnesses.

DANIEL F. LEPLEY.

Witnesses:

W. H. SoissoN, BAnNn'rr C. BURKHARDT. 

